One way roller clutches typically have a cage that provides a plurality of evenly spaced, generally rectangular pockets. Each pocket contains a roller and an individual roller energizing spring. The energizing springs are most commonly stamped from flat, resilient spring steel stock with generally V shaped folds. The springs may be of the type in which the folds are comprised of axially opening leaves, as shown in coassigned U.S. Pat. No. 4,850,464. In clutches of this type, the springs are usually just seated within a cage pocket, without a special latch structure on the end of the spring to physically tie it to the cage. The orientation of the leaves is not conducive to such a latch structure.
The other common accordion spring configuration has spring folds that are radially opening, as disclosed in coassigned U.S. Pat. No. 4,088,211. Since the pockets and the cage cross bars that make up the pockets are radially directed, it is convenient to tie the springs to the cage by pushing one of the spring's folds radially over a cage cross bar while a latch lanced out of the very end leaf of the spring clicks under an adjacent surface of the cage. The fold used to mount the spring, obviously, becomes inactive in terms of energizing the roller, and may be squared off in order to better conform to the cross bar. The latch retains the spring's mounting fold from pulling radially off of the cage cross bar. Structural changes to improve the security of this spring mounting system have generally involved new and more complex end leaf latch mechanisms, as shown in coassigned U.S. Pat. Nos. 4,850,462 and 4,782,928. These new latch designs make better use of the latching surfaces available on a conventional cage, but do not change the cage structure itself.
The standard cage and spring design of the type disclosed in the older U.S. Pat. No. 4,088,211 is still very commonly used, because it is simple and easy to manufacture, and is shown in FIGS. 1 through 5 of the accompanying drawings. A cage, indicated generally at 10, is of the metal folded type, with a series of box shaped roller pockets 12. Each pocket 12 is defined at one end by a radially directed cage cross bar 14 which, in turn, is adjacent to a circumferentially directed cross bar 16, separated therefrom by a radially opening slot 18 of width W that is adjacent to the radially outer edge of cross bar 16. Each part of cage 10 has basically the same thickness, being folded and stamped from a single thickness of metal stock. The standard energizing spring, indicated generally at 20, has a pair of active V shaped folds, a middle fold 22 and front fold 24, the forwardmost leaf 26 of which is curved to match a cylindrical roller 28. The spring fold 30 adjacent to the middle active fold, which is used as the mounting fold, is squared off, with front leaf 32 and rear leaf 34, which, while they are not intended to compress and expand, are resilient nonetheless. However, that resilience does not come into play since the free state separation of the leaves 32 and 34, shown at S, is basically equal to the thickness of cage cross bar 14 over which it is to be seated. This means that the leaves 32 and 34 do not pinch the faces of the cross bar 14 with any significant force when they are seated over it, nor are they intended to do so. Even if the leaves 32 and 34 were stamped such that, in the free state, the ends of the leaves 32 and 34 touched, like the ends of a hair pin, the pinching force they could apply to the cross bar 14 would be insubstantial. Furthermore, it would be almost impossible to stamp the leaves 32 and 34 with a free state pinched in configuration. In fact, if anything, the leaves 32 and 34 will, in a pre installation free state, be spread apart slightly from an absolutely parallel relationship, as shown. Therefore, the mounting fold 30 must be retained to the cross bar 14 by a latch 38 lanced out of the endmost spring leaf 36. Pre-installation, the latch is spaced from the mounting fold rear leaf 34 by a distance X that is greater than W. This assures that, as the mounting fold 30 is pushed radially in and down over radial cross bar 14, endmost leaf 36 will radially enter, and drag along the edge of, slot 18, until the latch 38 clicks past the edge of slot 18 and beneath the adjacent cross bar 16 to retain mounting fold 30 against radial disassembly, as shown in FIG. 3. However, for the reasons noted, the mounting fold's front leaf 32 is not held against the cage cross bar 14 with any great force. When installed, spring 20 sits in a pocket 12, ready to have a roller 28 installed against its forwardmost leaf 26.
This retention scheme for spring 20 leads to several problems, both during shipping and handling of the clutch, and during operation. As shown in FIG. 4, when a roller 28 has been installed in pocket 12 and against the curved leaf 26, it is the resilience of the compressed spring 20 that presses the roller 28 into the forward edge of the pocket 12 to retain it in the cage 10. This roller retention brace is weak at best, although sufficient if the cage 10 is handled carefully. If the cage 10 is jostled, however, as shown in FIG. 4, the spring 20 can flip up and out of the pocket 12 as the spring curved leaf 26 slips off of the roller 28 and the untensioned mounting fold front leaf 32 spreads away from the cage cross bar 14. During operation, the cage 10 is installed between a pair of inner and outer clutch races 40 and 42, as shown in FIG. 5. It is the expansion and contraction of spring 20 that keeps roller 28 in a lock up ready position, ready to jam between the races 40 and 42. Spring 20 reacts against and from the cage radial cross bar 14. The stability and operational effectiveness of spring 20 depends on how securely and stably it is tied to cross bar 14. Cage 10 will spin rapidly at various times, with the inner race 40, putting a centrifugal force on the spring 20 that tends to throw it radially outwardly. Because of the lack of a strong grip on cage cross bar 14 by the spring mounting fold 30, its front leaf 32 can again spread away from the cage cross bar 14, allowing the middle fold 22 to squirt outwardly and rub on the outer race 42.